This invention relates in general to electrical terminations and terminating methods and deals more particularly with improved terminations for electrical circuit traces on panels and printed circuit boards and methods for making such terminations.
This invention relates in general to electrical connections and terminations and deals more particularly with improved terminations for circuit traces disposed on surfaces of panels, circuit boards and the like and particularly termination of metallic circuit traces of the etched copper variety.
Such circuit traces are suitable for termination by several standard termination techniques, including edge connection for printed circuit boards employing a stiffener or paddle board approach, soldering or welding including laser techniques, contact piercing type print terminations and pressure or spring termination designs. However, each of the aforesaid generally accepted techniques has limitations. Termination techniques which employ solder, for example, may be wholly unacceptable for many medical applications. Conventional mechanical termination techniques often prove troublesome where the device having the terminations is or may be exposed to frequent shock and/or vibration, as, for example, in automotive applications. Further, many of the standard termination techniques impose limitations upon the spacing which must be provided between adjacent terminations making these techniques generally unsuitable for use where high-density in-line termination is required.
The present invention is concerned with the afore described general problems.
Accordingly, it is the general aim of the present invention to provide an improved metallic circuit trace termination highly resistive to shock and vibration and which enables maximization of termination density.
In accordance with the present invention, a printed circuit termination comprises a panel at least a portion of which is substantially rigid, defines a beam, and has generally parallel upper and lower surfaces, at least one of the surfaces defining a substrate. A circuit trace carried by the substrate has a terminal portion which extends along a portion of the substrate defined by the beam. A resilient compressible electrical conductor is disposed in overlying electrical contacting engagement with the terminal portion. The termination further includes an ultrasonically weldable cradle assembly formed by a cradle member and an energy director cap member. The energy director cap member cooperates in assembly with the cradle member to define a termination barrel receiving and confining therein at least parts of the beam, the terminal portion, and the resilient compressible electrical conductor. The cradle and cap members are ultrasonically welded together along a plane of joinder and maintain under compression that portion of the resilient compressible electrical conductor which is disposed within the termination barrel and which overlies the terminal portion of the circuit trace, whereby the electrical conductor is continuously resilient biased into electrical contacting engagement with the terminal portion of the circuit trace. In accordance with a method of the invention, a compressibility factor is determined for the resilient compressible conductor and is employed in dimensioning the termination barrel so that the resilient conductor is maintained in a compressed condition within the termination barrel. The energy stored in the compressed resilient conductor maintains the integrity of the termination.